Asp.net POST parameter always null

Question

For passing an email address I'm using ajax with POST as type.

$.ajax({
    url: "api/Search/UserByEmail",
    type: "POST",
    data: JSON.stringify({ emailAddress: userEmail }),
    contentType: "application/json;charset=utf-8",
    dataType: "json",
    success: function (data) { ... }
});

Controller:

[HttpPost]
public IEnumerable<Object> UserByEmail([FromBody] string emailAddress) { ... }

That's what Fiddler says:

POST http://localhost:52498/api/Search/UserByEmail HTTP/1.1
Accept: application/json, text/javascript, */*; q=0.01
Content-Type: application/json;charset=utf-8
X-Requested-With: XMLHttpRequest
Referer: http://localhost:52498/#
Accept-Language: de-DE
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)
Host: localhost:52498
Content-Length: 35
DNT: 1
Connection: Keep-Alive
Pragma: no-cache

{"emailAddress":"[email protected]"}

Why is the emailAddress parameter always null?

This looks fine to me, have you tested constructing a request with Fiddler and posting manually? Most likely problem is with the JSON data but I can't see anything wrong with it from here. You could also try removing the [FromBody] attribute. — James
– James, Commented Oct 2, 2013 at 8:09
When I take out [FromBody], my method is not even invoked. Here's the Routing: config.Routes.MapHttpRoute( name: "UserByEmailRoute", routeTemplate: "api/Search/UserByEmail", defaults: new { controller = "Search", action = "UserByEmail" } ); — Explicat
– Explicat, Commented Oct 2, 2013 at 10:37
that probably makes sense, it would be expecting you to post to api/Search/UserByEmail/emailAddress without that - just trying to rule out things that may be causing the problem :) In Fiddler, if you post [email protected] as the body does it work? — James
– James, Commented Oct 2, 2013 at 10:39

Marko · Accepted Answer · 2013-10-02 09:09:00Z

1

 // JS - jQuery 
 $.ajax({
        url: "/Home/UserByEmail",
        type: "POST",
        data: { emailAddress: "[email protected]" },
        dataType: "json",
        success: function (data) { if(data != null) { alert(data.toString()); } }
    });



  [Serializable]
  public class EmailFormModel {
     public string emailAddress { get; set; }
  }

    [HttpPost]
    public JsonResult UserByEmail(EmailFormModel emailFormModel)
    {
        bool ok = emailFormModel.emailAddress != null;
        return Json(new { ok }); 
    }

Use a formModel and put a serializable attribute on the class and it will serialize your javascript automatically to a C# equivalent. And you don't need to use Json-stringify.

Note a removed the // contentType: "application/json;charset=utf-8", declaration from the ajax-method. I've actually never used it.

edited Oct 2, 2013 at 9:09

answered Oct 2, 2013 at 8:03

Marko

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9 Comments

James Over a year ago

"You don't need to use JSON.stringify" - you do if you want to pass data as JSON...

Marko Over a year ago

No if you have a serializable class as a parameter into your method it will automatically convert the javascript object to C#. And I have used this a lot myself, and it's nice!!

James Over a year ago

Yes, the point I am making though you are no longer working with JSON - the data is converted to a query string and appended to the URL.

Marko Over a year ago

Yeah but it's still a HTTP POST!

James Over a year ago

yep it is, but like I said you are no longer posting JSON from the client so application/json would have to also change to application/x-www-form-urlencoded.

|

Mathew Thompson · Accepted Answer · 2013-10-02 08:03:09Z

0

I think the JSON.stringify could be your problem. MVC will handle the serialization/deserialization of parameters for you, change it to:

data: { emailAddress: userEmail }

answered Oct 2, 2013 at 8:03

Mathew Thompson

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2 Comments

Mathew Thompson Over a year ago

@user2558051 Also, take out that FromBody attribute, I'm pretty sure you don't need that (I've never ever heard of it!)

James Over a year ago

@mattytommo you generally do need the [FromBody] attribute with the WebAPI...however, I get the feeling that might be the problem here as well (see my comment).

Joseph King · Accepted Answer · 2015-01-08 18:47:49Z

0

Modify the data property in the original ajax call to

data: '"' + userEmail + '"',

Getting some of these Web API calls to work can sometimes be a little tricky

answered Jan 8, 2015 at 18:47

Joseph King

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